Stroke remains a major public health problem with a disproportionate impact on blacks and Hispanics. Studies in Northern Manhattan have demonstrated that blacks and Hispanics have a greater stroke incidence and more frequently have small vessel and intracranial atherosclerotic stroke than whites. The reasons for these race-ethnic disparities are not entirely clear. Over the last 5 years, enrollment of a population-based, prospective cohort of 3298 stroke-free adults was completed and follow-up commenced. This collaborative study is the first prospective cohort study among whites, blacks and Caribbean Hispanics living in the same community. This competitive renewal will support continued follow-up and outcome detection and expansion of data collection in this cohort. The aims are to evaluate the relationship between vascular outcomes (stroke, MI, and vascular death) and insulin resistance, carotid intima-media thickness, carotid distensibility, and quantitative MRI measures of vascular subclinical brain disease and to determine if MRI subclinical disease accounts for race ethnic differences in cognitive impairment. [unreadable] [unreadable] To accomplish these aims further data collection using our population-based, prospective cohort study is proposed. Stored baseline serum will be used to measure fasting insulin levels to evaluate insulin resistance. High-resolution carotid imaging data will be collected at subsequent visits to expand our measurements of subclinical carotid disease to 1500 subjects. MRIs and a neuropsychological battery emphasizing frontalexecutive domains will be done on 1400 subjects and quantitative analyses performed to measure white matter hyperintensities, silent infarcts, and silent cerebral microbleeds. Subjects will be followed by annual telephone interviews to ascertain stroke, MI, death, and changes in cognitive state. In-person assessment will be done for all subjects who screen positive and a 10 percent random sample of the cohort. Community stroke surveillance will be maintained to insure stroke detection among the cohort. Specific diagnostic committees classify stroke, MI andvascular death. The strengths of this cohort study are the wealth of baseline data already assembled, the triethnic composition residing in the same community, the outstanding follow-up record, the evaluation of putative risk factors, and the innovative assessment of MRI subclinical disease and carotid subclinical disease. This cohort study will help fill the gaps in our knowledge of the epidemiology of stroke and cognitive impairment in minority populations and lead to new insights on innovative ways to detect those at greatest risk of the consequences of vascular disease.